A dimeric molybdenum complex with both terminal and bridging sulfido ligands, (C5H4CH3MoS2)2 has been characterized. Reactions of this complex with nucleophiles and electrophiles will be investigated in order to compare the lability characteristics of the different sulfido ligands. Synthetic routes for the preparation of new molybdenum complexes with terminal sulfido ligands or with disulfide ligands will be investigated. Reaction studies of these product complexes will also be carried out. Dimeric molybdenum complexes with briding dithiolate ligands have been found to catalyze the reduction of acetylene to ethylene and to react reversibly with isocyanides. Kinetic and mechanistic details of these reactions will be studied. We propose to investigate reactions of the molybdenum complexes with dinitrogen, nitriles, and cyanide ion.